The AL Vet is correct that the load on the pony from the compression tells one that a lot more heat is being generated by the loaded pony.

I typically run my pony longer on decom just to warm up the pony and get the oil circulating in the main. When the pony gets warmed a bit, go to full throttle on the pony, flip to compression for a few seconds and hit the main throttle. Usually less than 15 seconds on compression to start unless it is below 30 degrees F. If one thinks about it, the compressed air is heating the surface of the cylinder so that when the air enters and is compressed, it is at a temperature that will ignite.

That is a good idea Ray to check the head temp with a pyro. Now if I can remember to do that next time I crank up the D4 or 112. I use them all the time to check block and tranny temps on the green stuff.

Shared oil between pony and main is old news, was standard for a very short time on D7/D8 and maybe others. There was a retrofit kit to separate them again..... not a good idea apparently.

Your idea that having the decompression pulled lets warmed air recirculate back into the intake manifold may be true, but you’re forgetting that the next stroke UP of the piston, the exhaust valve opens and most of the warm air that has been conserved is exhausted, only to be replaced by more cold air coming in the air cleaner.

I’m glad your main engine starts right up as soon as you flip the decompression to run, but when the engine and air are cold, cranking it under compression is the fastest way to get it warmed up and started...... Unless you believe in the ether bunny!

"ccjersey" wrote:

Shared oil between pony and main is old news, was standard for a very short time on D7/D8 and maybe others. There was a retrofit kit to separate them again..... not a good idea apparently.

Your idea that having the decompression pulled lets warmed air recirculate back into the intake manifold may be true, but you’re forgetting that the next stroke UP of the piston, the exhaust valve opens and most of the warm air that has been conserved is exhausted, only to be replaced by more cold air coming in the air cleaner.

I’m glad your main engine starts right up as soon as you flip the decompression to run, but when the engine and air are cold, cranking it under compression is the fastest way to get it warmed up and started...... Unless you believe in the ether bunny!

-if you live above the 49 parallel.....you believe in the Easter Bunny...and the Ether Bunny (in moderation)

-there's quite a large window when it comes to a diesels static compression ratio...anywhere from 13 to something like 22 to one...and it seems the higher compression diesels start better, to me at least..probably harder to crank but that extra heat generated in the cylinder fires off sooner..

My knowledge and understanding with diesel engines has grown quite a bit since i first got my tractor. So, maybe part of it is I am noticing things now that I or most people would have not really noticed before.

I've got a much better idea of how to start the engine than what I used to have.

i think the throttle position when starting is important too, you are injecting cold oil into a cold cylinder....(can you flood a diesel engine like a gasoline engine??, I dunno...)

-so I usually adjust the throttle to what i feel would be just above idle position when warm...crank it and as soon as it fires up and smooths out a bit, check oil pressure..slowly give it more throttle to warm up...

-just the way i do it...seems to work for me:tongue:

NEVER crank engine over with starting engine with the diesel throttle open! Your just loading up the cylinders with raw fuel and washing all the oil off the sleeves and rings. Always leave fuel off until on compression and when ready to start. BUILD UP THE HEAT FIRST!!!!